1. Test overview.

This test is used to verify that the belts of the 120 film carrier is sufficiently tightened. This test is similar in its operation than with of MOTOR INTENSITY. This one having been made beforehand, the primary tension therefore correct. If the test 120 motor intensity fails, this means that the film carrier has a problem.
The software always controls the current sent to the motor, which represents the image of the tension on the belts: the more the belts are tightened, the greater the effort will be to turn the motor, therefore the amount of current required will be larger.
The advance of film during the scanning must be maintained as steady as possible, as the software controls the amount of current sent to the motor according to the efforts required. The current must be as stable as possible, however variations may occur due to the " off centred effect " of the gears.
The tension measurement of the belts is made in both directions of the motor (corresponding to the prescan and the scan).
If the belts of the film carrier are not sufficiently tightened, the film can slip during the scanning and this can generate a incorrect framing of the images. On the other hand, if the belts are overtightened, the risk of overtorque (overloaded motor) will become greater.

2. Test conditions.

This test relates to the 120 film carrier inserted in the scanner.
The 120 film carrier must to be inserted in the scanner to carry out this test.
No film is necessary for this test.
The acceptance of the test is automatic.
No parameter is saved.

3. Pre-requirements.

As the belt tension is done automatically by a spring, there is no intial conditions for this test.

4. Test realisation.

Click on RUN to execute the test. The motor will turn during 15 seconds in one direction then 15 seconds in the other direction (these 15 seconds correspond to a turn of film belt carrier.
At the end of the test, in the result window, a red and blue curve will be displayed (corresponding to both directions of rotation of the test). In the execution window, quantified results for each curve will be displayed. The test will automatically be accepted or rejected according to these 2 curves results.

5. Test acceptance.

The software is used mainly for 3 criteria (for each direction of rotation, that is to say 6 in total) to accept or reject the test :

• The average of the curve: must lie between 104 and 119,8
• The maximum of the curve: must be lower than (real average + 8%)
• The minimum of the curve: must be higher than (real average - 8%)

6. Other affected tests.

If the tension of the belts of the 120 film carrier is modified in significant proportions, the following tests should be remade :

• 120 cal play.
• 120 cal encoder 2.
• 120 cal RGB IR.

If the tension of the belts were modified very little (for example, the average passed from 71 to 62), it is probably not useful to remake all these tests

7. Trouble shooting.

• The average in one direction is much weaker than in the other direction : this means that the gear motor is damaged, it should be changed.


• The minimum or the maximum is outside the spec : This is due to the gears off centred effect. Check that the both gears(motor and film carrier) are correctly assembled on their axis (that they run smoothly). Check that all the gears of the film carrier turn freely. Also note that the more tension on the belts, the greater the off centred effect will show (creating a significant undulation on the curve).